SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1237 AM CDT Thu Aug 15 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN KS INTO PARTS OF THE MID MS VALLEY AND MIDWEST... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the Midwest, mid Mississippi Valley, and central Plains on Thursday. Damaging winds and large hail should be the main threats, but a couple tornadoes may also occur. A few strong storms may also develop across parts of the Northeast. ...Central Plains to the Mid Mississippi Valley... Weak mid-level height falls will spread across the mid Mississippi Valley today ahead of a short-wave trough that will approach western IA/northwest MO by early evening. Early in the period, a weak short-wave trough will be responsible for inducing multiple thunderstorm clusters across the Midwest, aided by LLJ that will translate into Lower MI by late afternoon. This early-day convection will be an extension of ongoing thunderstorm clusters that currently extend from central IA into eastern KS. This activity will propagate downstream as the LLJ shifts into the Great Lakes ahead of the weak disturbance. While locally severe gusts and hail could accompany this activity, considerable amount of precip and modest lapse rates do not favor widespread severe. Of more concern, strong boundary-layer heating is expected across much of the Plains into portions of the mid MS Valley. As a result, strong buoyancy will develop along the eastern edge of this steeper lapse-rate plume. Latest model guidance suggests very strong instability (MLCAPE >3000 J/kg) will materialize by mid afternoon from portions of eastern KS/MO into southeast IA. High-level diffluent flow will favor storm-top venting and scattered robust thunderstorms are expected to develop ahead of the short wave. Thunderstorms should concentrate along a synoptic front that will arc from southeast MN-eastern IA-northern MO-southeast KS-northern OK by late afternoon. Deep-layer shear should be adequate for supercells and wind/hail can be expected with the most robust updrafts. High-based thunderstorms are also expected to develop along the trailing boundary into the southern Plains where surface temperatures will easily rise through the upper 90s to near 100F. Dry adiabatic 0-3km lapse rates favor strong downdrafts as PW values will be seasonally high (1.5-1.75 inches). ...New England region... Upper troughing will hold across New England today with cool mid-level temperatures and modest northerly flow at 500mb. Strong boundary-layer heating will allow convective temperatures to be breached by 19z and scattered convection is expected to develop within a sheared environment that favors robust multi-cell updrafts. Some of this activity could generate strong gusts and marginally severe hail. Convection will be diurnally driven and should weaken with loss of daytime heating. ..Darrow/Halbert.. 08/15/2024 Read more

MD 1904 CONCERNING SEVERE THUNDERSTORM WATCH 622... FOR SOUTHEASTERN NEBRASKA...NORTHEASTERN KANSAS...SOUTHWESTERN IOWA...AND NORTHWESTERN MISSOURI
Mesoscale Discussion 1904 NWS Storm Prediction Center Norman OK 0920 PM CDT Wed Aug 14 2024 Areas affected...southeastern Nebraska...northeastern Kansas...southwestern Iowa...and northwestern Missouri Concerning...Severe Thunderstorm Watch 622... Valid 150220Z - 150415Z The severe weather threat for Severe Thunderstorm Watch 622 continues. SUMMARY...Local severe risk continues across the Middle Missouri Valley area. DISCUSSION...Latest radar loop shows strong/locally severe storms ongoing within WW 622, though gradually growing upscale into a more linear configuration as compared to earlier. This has lessened the tornado threat that existed near the remnant outflow in northeastern Kansas, with risk now primarily in the form of hail, and locally strong/gusty winds. As the boundary layer gradually stabilizes, risk for severe-caliber wind gusts should slowly lessen. Still, some eventual expansion of the watch eastward may be needed a bit later this evening, as storms near the eastern edge of the WW. ..Goss.. 08/15/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...EAX...OAX...TOP...ICT... LAT...LON 38879796 39679714 40259657 40629654 40919709 41289698 41919562 41819344 41649267 40779281 38829479 38879796 Read more

WW 0622 Status Updates
STATUS REPORT ON WW 622 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 N EMP TO 40 WSW LWD TO 10 WNW DSM. ..GOSS..08/15/24 ATTN...WFO...DMX...OAX...EAX...TOP...ICT...GID... STATUS REPORT FOR WS 622 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IAC121-159-175-150440- IA . IOWA COUNTIES INCLUDED ARE MADISON RINGGOLD UNION KSC005-017-043-045-059-085-087-091-103-111-115-139-177-209- 150440- KS . KANSAS COUNTIES INCLUDED ARE ATCHISON CHASE DONIPHAN DOUGLAS FRANKLIN JACKSON JEFFERSON JOHNSON LEAVENWORTH LYON MARION OSAGE SHAWNEE WYANDOTTE MOC003-021-025-033-047-049-061-063-075-079-081-095-107-117-129- 165-177-227-150440- MO Read more

WW 622 SEVERE TSTM IA KS MO NE 142230Z - 150600Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 622 NWS Storm Prediction Center Norman OK 530 PM CDT Wed Aug 14 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southwestern Iowa Central to northeastern Kansas Northwestern Missouri East-central and southeastern Nebraska * Effective this Wednesday afternoon and Thursday morning from 530 PM until 100 AM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Severe thunderstorms are expected to develop in the next couple hours near the western end of the watch and move roughly eastward while increasing in coverage through the evening. Large to isolated very large hail is possible early, while the severe-gust threat increases into evening. A tornado or two also is possible -- mainly over a part of the watch across northeastern KS, near an outflow boundary. The severe thunderstorm watch area is approximately along and 90 statute miles east and west of a line from 30 miles south southeast of Manhattan KS to 35 miles north northeast of Omaha NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 26030. ...Edwards Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 PM CDT Wed Aug 14 2024 Valid 150100Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE MISSOURI VALLEY... ...SUMMARY... Scattered severe thunderstorms capable of all hazards remain possible this evening across portions of the middle Missouri Valley. ...01z Update... Well-defined short-wave trough is ejecting across the High Plains early this evening. LLJ is beginning to increase across eastern KS ahead of this feature, and is forecast to intensify across northwest MO/southern IA later this evening. Scattered severe thunderstorms have developed ahead of the surface front from southeast NE into central KS. This activity should propagate downstream into a favorable zone of low-level warm advection after sunset, aided by increasing LLJ. Very moist, buoyant airmass exists ahead of the convection with MLCAPE values in excess of 3000 J/kg, extending as far northeast as northwest MO. Some supercell concern exists along this corridor despite the modest deep-layer shear. 00z sounding from TOP exhibited 30kt surface-6km bulk shear, with 0-3km SRH on the order of 400 m2/s2. Hail/wind threat exists with this activity along with some tornado risk. Upstream, secondary low-amplitude short-wave trough is shifting east across WY early this evening. Scattered robust convection has developed ahead of this feature, arcing from the southern Black Hills into southeast WY. Another band of organized robust storms has developed across eastern SD. Isolated marginally severe gusts or hail could be noted with this activity for the next few hours. ..Darrow.. 08/15/2024 Read more

MD 1903 CONCERNING SEVERE THUNDERSTORM WATCH 622... FOR PORTIONS OF NORTHEASTERN KANSAS AND SOUTHEASTERN NEBRASKA...AND INTO SOUTHWESTERN IOWA AND NORTHWESTERN MISSOURI
Mesoscale Discussion 1903 NWS Storm Prediction Center Norman OK 0709 PM CDT Wed Aug 14 2024 Areas affected...portions of northeastern Kansas and southeastern Nebraska...and into southwestern Iowa and northwestern Missouri Concerning...Severe Thunderstorm Watch 622... Valid 150009Z - 150145Z The severe weather threat for Severe Thunderstorm Watch 622 continues. SUMMARY...A few severe storms -- including a persistent supercell -- are now ongoing across portions of WW 622 near the northeast Kansas/southeast Nebraska border. Large hail remains the primary threat, though a damaging outflow gust and/or brief tornado are also possible. DISCUSSION...Latest radar loop across the Mid-MO Valley area shows several vigorous updrafts, a couple of which have exhibited transient rotational signatures per area WSR-88D data. The most organized/long-lived cell is moving northeastward across Gage County, though this storm too now appears to be weakening. Overall, the environment supports strong/rotating storms; the combination of a moist (70s dewpoints) and very unstable (3000-plus J/kg mixed-layer CAPE) environment, combined with the presence of a northwest-to-southeast remnant outflow providing focused low-level ascent, suggests additional strong/severe storm development over the next couple of hours. In addition, recent CAM output continues to hint at potential for storm development near/ahead of a surface cold front slowly advancing across central Nebraska, which would be expected to move into/across northwestern portions of WW 622 later this evening. Given a similarly sheared/unstable environment ahead of the front, potential for large hail and damaging wind gusts would likely accompany these storms, presuming development as anticipated. ..Goss.. 08/15/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...OAX...TOP...ICT... LAT...LON 38889796 39529703 40229695 40769638 40979568 40249512 39359533 38699641 38639754 38889796 Read more

WW 0622 Status Updates
STATUS FOR WATCH 0622 HAS NOT BEEN ISSUED YET Read more

No watches are valid as of Wed Aug 14 21:31:02 UTC 2024.

MD 1900 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE TX/OK PANHANDLES...FAR NORTHWEST OK...AND SOUTH-CENTRAL KS
Mesoscale Discussion 1900 NWS Storm Prediction Center Norman OK 0300 PM CDT Wed Aug 14 2024 Areas affected...Portions of the TX/OK Panhandles...far northwest OK...and south-central KS Concerning...Severe potential...Watch unlikely Valid 142000Z - 142200Z Probability of Watch Issuance...20 percent SUMMARY...Isolated strong/severe downbursts are possible through the afternoon, though a watch is not expected here. The severe threat will increase later this afternoon/evening with northeastward extent. DISCUSSION...Boundary-layer cumulus is gradually deepening along a pre-frontal heat axis/confluence zone extending from the TX Panhandle northeastward into south-central KS. Over the TX Panhandle, cumulus is deeper and isolated convective initiation is underway. During the next few hours, continued heating/destabilization should aid in isolated to widely scattered high-based thunderstorms along the heat axis, and potentially along a slow-moving cold front over southwest KS. Surface temperatures climbing into the upper 90s/lower 100s and associated steep low-level lapse rates will support strong to locally severe downbursts with any high-based storms that can initiate through the afternoon. Modest deep-layer flow/shear (especially from the TX Panhandle into south-central KS) should generally limit storm longevity, and generally weak large-scale ascent casts uncertainty on overall storm coverage. Therefore, a watch is not expected for this area. Both instability and deep-layer wind shear increase with northeastward extent into central/northeast KS, and any storms that spread/develop into this area will pose a greater severe threat later this afternoon into the evening. ..Weinman/Thompson.. 08/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...OUN...DDC...AMA... LAT...LON 37449851 35280095 35230148 35370188 35670213 35960211 36260178 37490047 38149975 38459943 38599922 38629887 38579848 38219816 37899819 37449851 Read more

MD 1901 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL SOUTH DAKOTA
Mesoscale Discussion 1901 NWS Storm Prediction Center Norman OK 0353 PM CDT Wed Aug 14 2024 Areas affected...central South Dakota Concerning...Severe potential...Watch unlikely Valid 142053Z - 142300Z Probability of Watch Issuance...20 percent SUMMARY...A cluster of thunderstorms may continue to slowly evolve to the west and northwest of the Pierre vicinity through 5-7 PM CDT, accompanied by occasional small to marginally severe hail and locally strong surface gusts. It is possible that the risk for potentially damaging wind gusts could increase later this evening. However, at least until then, it appears unlikely that a severe weather watch will be needed. DISCUSSION...Within lee surface troughing, inhibition is eroding with continuing insolation, for a destabilizing boundary layer near a modest low centered near Pierre. This is being aided by mid-level cooling overspreading the high plains, associated with the leading edge of troughing crossing the northern Rockies, which appears to be providing support for an evolving line of convection to the west of Mobridge into the Philip vicinity. A gradual further upscale growth appears possible during the next few hours, as convection acquires increasing inflow of unstable boundary-layer air becoming characterized by CAPE up to 2000 J/kg. In the presence of south-southwesterly deep-layer mean flow on the order of 10-15 kt, storm motions will remain slow initially. However, modest shear, aided by veering of wind fields with height, might slowly contribute to increasing organization into early evening, particularly as convective outflow supports an increasingly prominent surface cold pool. Once this occurs, the risk for strong to severe surface gusts may begin to increase. Until then, though, more localized strong surface gusts and occasional small to marginal severe hail appear the primary potential severe hazards. ..Kerr/Thompson.. 08/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR... LAT...LON 45990078 45659962 43939945 43900110 45490153 45990078 Read more

MD 1902 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF NORTHEAST KS...SOUTHEAST NE...FAR NORTHWEST MO...AND FAR SOUTHWEST IA
Mesoscale Discussion 1902 NWS Storm Prediction Center Norman OK 0357 PM CDT Wed Aug 14 2024 Areas affected...Portions of northeast KS...southeast NE...far northwest MO...and far southwest IA Concerning...Severe potential...Watch possible Valid 142057Z - 142330Z Probability of Watch Issuance...60 percent SUMMARY...The area is being monitored for increasing severe potential this afternoon into the evening. Timing of thunderstorm development is uncertain, though an eventual watch issuance appears likely for parts of the area. DISCUSSION...Latest surface analysis depicts a warm front/modifying outflow boundary extending east-southeastward across northeast KS -- from a weak frontal-wave low over north-central KS. North of the boundary, billow clouds continue to erode from south to north as the antecedent outflow continues to destabilize amid strong diurnal heating. Here, steep mid-level lapse rates atop rich/sheltered boundary-layer moisture (upper 60s/lower 70s dewpoints) will result in strong surface-based instability. However, additional heating will be needed (especially with northward extent) to erode lingering inhibition (see OAX 19Z special sounding). Thunderstorms should eventually initiate near the frontal-wave low, near the warm front, and possibly to the north along a differential heating boundary, possibly aided by an approaching midlevel trough. Storms will spread eastward into the increasingly favorable environment -- characterized by 30-40 kt of effective shear, strong instability, and clockwise-curved low-level hodographs (200-300 m2/s2 effective SRH). This will favor organized storms, including the potential for supercells and organized clusters, capable of damaging winds, large hail, and perhaps a couple tornadoes. Timing of thunderstorm development and intensification is still uncertain, though an eventual watch issuance is likely for parts of the area. ..Weinman/Thompson.. 08/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...OAX...TOP...ICT...GID... LAT...LON 38899778 39289797 39729796 40439769 41109738 41429716 41479676 41429591 41109560 40169532 39629532 39279555 38769605 38569643 38499682 38659739 38899778 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0319 PM CDT Wed Aug 14 2024 Valid 161200Z - 221200Z Fire weather concerns are expected to primarily reside across portions of the Great Basin this weekend, perhaps persisting into next week. Long-range ensemble guidance continues to show low probabilities for wetting rainfall across much of CA, NV, and central TX through the forecast period. This will be driven by a gradually amplifying upper-level regime with upper ridging over the south-central CONUS and the establishment of a robust trough along the West Coast. Fuels across both regions should continue to dry and will support fire weather concerns if/when winds can approach critical thresholds. ...D4/Sat to D5/Sun - Nevada... A mid-level impulse embedded within the mean upper trough is forecast to pivot across northern CA into the northern Great Basin through D4/Saturday. Strong mid-level flow associated with this feature will overspread the central to northern Sierra Nevada, resulting in strengthening downslope winds with somewhat widespread dry/breezy conditions across western and central NV. Afternoon relative humidity values in the teens should be common with winds between 15-25 mph. Given antecedent dry fuels, fire weather concerns are expected, though confidence in the coverage of 20+ mph remains limited away from the immediate lee side of the Sierras, and precludes higher risk probabilities. Breezy downslope winds should persist into D5/Sunday, but may be more limited in scope given weaker mid-level winds compared to Saturday. Overall, a west/southwesterly mid/upper-level flow regime should persist into early next week and may continue to support periods of elevated fire weather conditions across NV. ...Texas... Recent fuel and fire reports from north-central TX and southern OK indicate that grasses and shrubs are undergoing rapid drying amid increasingly hot temperatures. Forecast highs through the forecast period are expected to exceed 100 F each day (likely reaching near 105 F for many locations). While areas north of the Red River may see occasional rain/thunderstorm chances later this week, little to no precipitation is expected across central to western TX. These hot/dry conditions will promote further expansion of burnable fuels and steadily increasing ERCs across the region. The building upper ridge will modulate the potential for surface winds to exceed critical threshold, but fire concerns may emerge if winds trend higher than currently forecast. ..Moore.. 08/14/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0319 PM CDT Wed Aug 14 2024 Valid 161200Z - 221200Z Fire weather concerns are expected to primarily reside across portions of the Great Basin this weekend, perhaps persisting into next week. Long-range ensemble guidance continues to show low probabilities for wetting rainfall across much of CA, NV, and central TX through the forecast period. This will be driven by a gradually amplifying upper-level regime with upper ridging over the south-central CONUS and the establishment of a robust trough along the West Coast. Fuels across both regions should continue to dry and will support fire weather concerns if/when winds can approach critical thresholds. ...D4/Sat to D5/Sun - Nevada... A mid-level impulse embedded within the mean upper trough is forecast to pivot across northern CA into the northern Great Basin through D4/Saturday. Strong mid-level flow associated with this feature will overspread the central to northern Sierra Nevada, resulting in strengthening downslope winds with somewhat widespread dry/breezy conditions across western and central NV. Afternoon relative humidity values in the teens should be common with winds between 15-25 mph. Given antecedent dry fuels, fire weather concerns are expected, though confidence in the coverage of 20+ mph remains limited away from the immediate lee side of the Sierras, and precludes higher risk probabilities. Breezy downslope winds should persist into D5/Sunday, but may be more limited in scope given weaker mid-level winds compared to Saturday. Overall, a west/southwesterly mid/upper-level flow regime should persist into early next week and may continue to support periods of elevated fire weather conditions across NV. ...Texas... Recent fuel and fire reports from north-central TX and southern OK indicate that grasses and shrubs are undergoing rapid drying amid increasingly hot temperatures. Forecast highs through the forecast period are expected to exceed 100 F each day (likely reaching near 105 F for many locations). While areas north of the Red River may see occasional rain/thunderstorm chances later this week, little to no precipitation is expected across central to western TX. These hot/dry conditions will promote further expansion of burnable fuels and steadily increasing ERCs across the region. The building upper ridge will modulate the potential for surface winds to exceed critical threshold, but fire concerns may emerge if winds trend higher than currently forecast. ..Moore.. 08/14/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Aug 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MIDDLE MO VALLEY... ...SUMMARY... Scattered severe thunderstorms capable of all hazards are possible late this afternoon through the evening across portions of the middle Missouri Valley. ...20z Update... No changes are needed to the current Convective Outlook. Across the Slight Risk region in KS/NE/MS/IA, air mass recovery has been ongoing in the wake of a morning MCS. Temperatures have warmed into the upper 70s to mid 80s with mid 70s dew points increasing as as a modified outflow boundary drifts slowly northeast. This region will be the focus for the main severe threat through the afternoon and evening as a surface low and attendant cold front move eastward into the region and modified outflow/pseudo warm front lifts northward. Initial supercell development is expected by late afternoon/early evening with potential for a tornado or two and large hail. Clustering of supercells into linear segments later in the evening will support an increasing risk in damaging wind through the evening/overnight. A Marginal Risk continues across the Great Basin into the northern Rockies as well as across the central/high Plains. Scattered thunderstorm development in these regions will pose potential for strong to severe wind and some instances of severe hail. ..Thornton/Thompson.. 08/14/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Wed Aug 14 2024/ ...MO Valley area this afternoon through tonight... An MCV over northwest IA will continue eastward today, while clusters of thunderstorms are ongoing this morning from central MO to northern AR within a low-level warm advection regime. Warm advection will slowly weaken through the day, but convective outflow with the central MO storm cluster may result in those storms persisting well into the afternoon while spreading southward. Otherwise, outflow from the morning convection will slowly modify from eastern KS into southeast NE, in advance of a midlevel shortwave trough over the central High Plains, and an associated surface cold front moving southeastward across northwest KS. The cold front and the front/outflow intersection will focus thunderstorm development late this afternoon/evening from central KS to southeast NE/southwest IA, and storms will subsequently spread eastward tonight as one or more storm clusters/MCSs across northern MO/southern IA. Low-level shear/hodograph curvature will be maintained this afternoon within the modifying outflow across the SLGT risk area, where semi-discrete supercells and a couple of tornadoes will be possible. Isolated very large hail (2-2.5 inches in diameter) will also with any persistent supercells, though the severe threat will transition primarily to damaging winds (60-75 mph) by late evening into tonight as storms grow upscale. Farther northwest, a separate clustering of storms is possible in central SD, south of the ongoing convection across southern ND. Surface heating in cloud breaks and weak ascent downstream from an ejecting midlevel trough will help focus thunderstorm development by 21-00z. Low-midlevel vertical shear will not be particularly strong and flow aloft will be strongly backed, which suggests a fairly quick growth into a line segment. Isolated damaging gusts and large hail will be possible for a few hours late this afternoon/evening. ...WY and vicinity this afternoon... An embedded vorticity maximum over southeast ID will progress eastward over WY this afternoon/evening. There will be sufficient low-midlevel moisture and surface heating for high-based thunderstorm development by early afternoon in advance of the vorticity maximum. Given steep low-level lapse rates and modest enhancement to midlevel flow (near 30 kt), strong outflow winds of 50-60 mph will be possible with this convection through the afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Aug 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MIDDLE MO VALLEY... ...SUMMARY... Scattered severe thunderstorms capable of all hazards are possible late this afternoon through the evening across portions of the middle Missouri Valley. ...20z Update... No changes are needed to the current Convective Outlook. Across the Slight Risk region in KS/NE/MS/IA, air mass recovery has been ongoing in the wake of a morning MCS. Temperatures have warmed into the upper 70s to mid 80s with mid 70s dew points increasing as as a modified outflow boundary drifts slowly northeast. This region will be the focus for the main severe threat through the afternoon and evening as a surface low and attendant cold front move eastward into the region and modified outflow/pseudo warm front lifts northward. Initial supercell development is expected by late afternoon/early evening with potential for a tornado or two and large hail. Clustering of supercells into linear segments later in the evening will support an increasing risk in damaging wind through the evening/overnight. A Marginal Risk continues across the Great Basin into the northern Rockies as well as across the central/high Plains. Scattered thunderstorm development in these regions will pose potential for strong to severe wind and some instances of severe hail. ..Thornton/Thompson.. 08/14/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Wed Aug 14 2024/ ...MO Valley area this afternoon through tonight... An MCV over northwest IA will continue eastward today, while clusters of thunderstorms are ongoing this morning from central MO to northern AR within a low-level warm advection regime. Warm advection will slowly weaken through the day, but convective outflow with the central MO storm cluster may result in those storms persisting well into the afternoon while spreading southward. Otherwise, outflow from the morning convection will slowly modify from eastern KS into southeast NE, in advance of a midlevel shortwave trough over the central High Plains, and an associated surface cold front moving southeastward across northwest KS. The cold front and the front/outflow intersection will focus thunderstorm development late this afternoon/evening from central KS to southeast NE/southwest IA, and storms will subsequently spread eastward tonight as one or more storm clusters/MCSs across northern MO/southern IA. Low-level shear/hodograph curvature will be maintained this afternoon within the modifying outflow across the SLGT risk area, where semi-discrete supercells and a couple of tornadoes will be possible. Isolated very large hail (2-2.5 inches in diameter) will also with any persistent supercells, though the severe threat will transition primarily to damaging winds (60-75 mph) by late evening into tonight as storms grow upscale. Farther northwest, a separate clustering of storms is possible in central SD, south of the ongoing convection across southern ND. Surface heating in cloud breaks and weak ascent downstream from an ejecting midlevel trough will help focus thunderstorm development by 21-00z. Low-midlevel vertical shear will not be particularly strong and flow aloft will be strongly backed, which suggests a fairly quick growth into a line segment. Isolated damaging gusts and large hail will be possible for a few hours late this afternoon/evening. ...WY and vicinity this afternoon... An embedded vorticity maximum over southeast ID will progress eastward over WY this afternoon/evening. There will be sufficient low-midlevel moisture and surface heating for high-based thunderstorm development by early afternoon in advance of the vorticity maximum. Given steep low-level lapse rates and modest enhancement to midlevel flow (near 30 kt), strong outflow winds of 50-60 mph will be possible with this convection through the afternoon. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Wed Aug 14 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES INTO THE OH/TN VALLEYS...MID SOUTH...OZARKS...SOUTHERN KS...NORTHERN OK... ...SUMMARY... At least isolated strong to severe thunderstorms may develop Friday over portions of the Great Lakes into the Ohio/Tennessee Valleys, and potentially across parts of the Ozarks into the central and southern Plains. ...Synopsis... A mid/upper-level trough is forecast to move slowly eastward across parts of the Great Lakes, Midwest, and Ohio Valley on Friday. A belt of enhanced mid-level flow should be present from the east-central Plains to parts of the mid MS Valley into the OH Valley, and related deep-layer shear should be sufficient for some updraft organization with thunderstorms that can develop through the period. A weak surface low should likewise move slowly eastward over the Great Lakes vicinity. A weak front/wind shift is forecast to extend south-southwestward from this surface low. ...Great Lakes into the Midwest and Ohio/Tennessee Valleys... Extensive convection may be ongoing Friday morning across the Ohio Valley vicinity. Some intensification of morning storms cannot be ruled out through the day, though the primary severe threat is currently expected with storms that will develop in the wake of early convection during the afternoon and evening. Diurnal heating and rich low-level moisture will support pockets of moderate to locally strong destabilization by late afternoon across parts of the Midwest and Ohio/Tennessee Valleys. Moderate midlevel flow will support sufficient deep-layer shear for storm organization, and a conditionally favorable severe environment may eventually develop over a broad region near/ahead of the front. Details of storm initiation and evolution remain unclear, due to the influence of morning convection and generally weak convergence near the surface front. However, a few stronger cells/clusters may evolve during the afternoon and evening, posing a threat of damaging wind and hail. Greater severe probabilities may eventually be needed, once confidence increases in the location of one or more favored corridors of severe potential within the broader risk area. ...Ozarks into parts of KS/OK... The trailing portion of the cold front will likely extend from southern MO into southern KS/northern OK by late Friday afternoon. At least isolated storm development will be possible in the vicinity of the front, with some signal for convection to persist into Friday night as it moves east-southeastward. Moderate to strong buoyancy and modestly supportive deep-layer shear could result in a threat of isolated strong/damaging gusts and hail with the more robust storms from late Friday afternoon into Friday evening. ..Dean.. 08/14/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 PM CDT Wed Aug 14 2024 Valid 151200Z - 161200Z The previous forecast remains on track with only minor adjustments needed based on trends in recent high-res ensemble guidance. Localized elevated conditions are possible across eastern NV tomorrow afternoon, but will most likely occur over areas where fuels are only modestly dry and/or have seen recent rainfall. See the previous discussion below for additional details. ..Moore.. 08/14/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Wed Aug 14 2024/ ...Synopsis... A mid-level shortwave trough is forecast to cross the northern California coast early Thursday morning and deepen over western Oregon during the afternoon hours, bringing with it multiple rounds of isolated dry thunderstorms across central and eastern Oregon. ...Dry Thunderstorms... Some dry thunderstorms are expected to be ongoing at the start of the period Thursday morning. However, the greatest likelihood for thunderstorms will be in the afternoon and early evening hours, where a mix of scattered wet/dry thunderstorms are forecast across central and eastern Oregon. Even though fuels are near or at the 90th annual percentile over much of Oregon, the mix of wet/dry thunderstorms and relatively slow storm motions should result in at least some wetting rainfall limiting the overall threat despite scattered storm coverage. ...Dry/Windy... Surface winds are expected to remain below Elevated fire-weather criteria, except for where diurnally and terrain-driven winds are locally maximized. Given the localized nature of the better surface winds, no highlights are expected at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1899 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR MUCH OF WYOMING
Mesoscale Discussion 1899 NWS Storm Prediction Center Norman OK 0112 PM CDT Wed Aug 14 2024 Areas affected...much of Wyoming Concerning...Severe potential...Watch unlikely Valid 141812Z - 142045Z Probability of Watch Issuance...5 percent SUMMARY...Widely scattered strong storms, some with small to marginally severe hail, appear likely to continue to develop with increasing potential to produce localized severe surface gusts through 3-5 PM MDT. DISCUSSION...A significant upper-level trough is in the process of slowly progressing east of the northern Intermountain Region into northern Rockies. Beneath the mid-level cold core of this feature, large-scale ascent and destabilization are contributing to an area of sustained convective development and embedded thunderstorms, with additional scattered thunderstorms initiating in advance of this cluster across the Absaroka, Wind River and Bighorn Ranges of Wyoming. Across downstream lower elevations, boundary-layer warming and mixing are well underway in response to insolation, with surface temperature/dew point spreads already exceeding 30 F at some locations. With further heating and cooling aloft, mixed-layer CAPE in excess of 500 J/kg (and perhaps locally up to around 1000 J/kg) is forecast to continue to develop through mid/late afternoon. As this occurs, scattered thunderstorm development is likely to be maintained and intensify. Beneath modestly sheared mean westerly flow, including speeds on the order of 25-30 kt in the cloud-bearing layer, stronger storms may be accompanied by small to, perhaps, marginally severe hail. And negative buoyancy, aided by melting and evaporative cooling, in downdrafts may increasingly support localized strong to severe surface gusts through 21-23Z. ..Kerr/Thompson.. 08/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...UNR...CYS...RIW...SLC...PIH... LAT...LON 44560819 44220616 43580501 41820495 41250589 41200812 41111017 42901021 43311103 43911109 44401005 44560819 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Aug 14 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN KS INTO PARTS OF THE MID MS VALLEY AND MIDWEST... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest, mid Mississippi Valley, and central Plains on Thursday. Damaging winds and large hail should be the main threats, but a couple tornadoes may also occur. ...Synopsis... A mid/upper-level trough is forecast to evolve into a closed low on Thursday over parts of central/northern MN. As this occurs, a surface low will move from parts of MN/IA toward the upper Great Lakes, as a trailing cold front moves through parts of the upper Midwest into the central/southern Great Plains. ...Midwest into the mid MS Valley vicinity... In the wake of morning convection, moist low-level southwesterly flow will support airmass recovery and robust destabilization by afternoon from parts of the east-central Plains into the mid MS Valley and Midwest. MLCAPE may increase into the 2500-4000 J/kg range, while some increase in midlevel flow across the warm sector will support effective shear of 30-45 kt, resulting in a conditionally favorable severe-thunderstorm environment across a relatively broad region. The details of convective development and evolution continue to be uncertain, with generally weak convergence expected along the primary front, and with the location of any outflow boundaries yet to be determined. However, isolated to widely scattered storm development will be possible during the afternoon and early evening, both near the front and any other remnant boundaries. A somewhat greater coverage of storms will be possible later Thursday evening from southern WI into parts of IL/MO, in response to a midlevel jet maximum moving through the base of the trough. Supercells with a threat of large hail, damaging wind, and a couple tornadoes will be possible with initial development during the afternoon and early evening, with some upscale growth and an increase in damaging-wind potential possible later in the convective evolution. Some threat for at least isolated damaging wind could persist into Thursday night, though the southern/eastern extent of any organized severe potential remains uncertain. ...Eastern NE into western/central IA... There is some signal for at least isolated storm development within a post-frontal regime across parts of NE/IA and vicinity, which would potentially be aided by a low-amplitude shortwave moving through the base of the larger-scale trough. The post-frontal environment will remain favorable for organized convection, with moderate to locally strong buoyancy and favorable midlevel lapse rates and deep-layer shear. Some threat for large hail and localized damaging wind could accompany any robust storms within this regime during the afternoon and evening. Greater severe probabilities may be needed for parts of this region if confidence in this scenario increases. ...Southern KS into OK... With robust daytime heating, a deeply mixed boundary layer is expected to develop along/south of the front across parts of southern KS into OK. While deep-layer shear should remain weak across most of this region, moderate to strong instability and steepened low to mid-level lapse rates should support mainly an isolated severe wind threat with high-based thunderstorms that can develop. Occasional hail may also occur with the strongest cores. ..Dean.. 08/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Aug 14 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN KS INTO PARTS OF THE MID MS VALLEY AND MIDWEST... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest, mid Mississippi Valley, and central Plains on Thursday. Damaging winds and large hail should be the main threats, but a couple tornadoes may also occur. ...Synopsis... A mid/upper-level trough is forecast to evolve into a closed low on Thursday over parts of central/northern MN. As this occurs, a surface low will move from parts of MN/IA toward the upper Great Lakes, as a trailing cold front moves through parts of the upper Midwest into the central/southern Great Plains. ...Midwest into the mid MS Valley vicinity... In the wake of morning convection, moist low-level southwesterly flow will support airmass recovery and robust destabilization by afternoon from parts of the east-central Plains into the mid MS Valley and Midwest. MLCAPE may increase into the 2500-4000 J/kg range, while some increase in midlevel flow across the warm sector will support effective shear of 30-45 kt, resulting in a conditionally favorable severe-thunderstorm environment across a relatively broad region. The details of convective development and evolution continue to be uncertain, with generally weak convergence expected along the primary front, and with the location of any outflow boundaries yet to be determined. However, isolated to widely scattered storm development will be possible during the afternoon and early evening, both near the front and any other remnant boundaries. A somewhat greater coverage of storms will be possible later Thursday evening from southern WI into parts of IL/MO, in response to a midlevel jet maximum moving through the base of the trough. Supercells with a threat of large hail, damaging wind, and a couple tornadoes will be possible with initial development during the afternoon and early evening, with some upscale growth and an increase in damaging-wind potential possible later in the convective evolution. Some threat for at least isolated damaging wind could persist into Thursday night, though the southern/eastern extent of any organized severe potential remains uncertain. ...Eastern NE into western/central IA... There is some signal for at least isolated storm development within a post-frontal regime across parts of NE/IA and vicinity, which would potentially be aided by a low-amplitude shortwave moving through the base of the larger-scale trough. The post-frontal environment will remain favorable for organized convection, with moderate to locally strong buoyancy and favorable midlevel lapse rates and deep-layer shear. Some threat for large hail and localized damaging wind could accompany any robust storms within this regime during the afternoon and evening. Greater severe probabilities may be needed for parts of this region if confidence in this scenario increases. ...Southern KS into OK... With robust daytime heating, a deeply mixed boundary layer is expected to develop along/south of the front across parts of southern KS into OK. While deep-layer shear should remain weak across most of this region, moderate to strong instability and steepened low to mid-level lapse rates should support mainly an isolated severe wind threat with high-based thunderstorms that can develop. Occasional hail may also occur with the strongest cores. ..Dean.. 08/14/2024 Read more